Cellulosic materials internally sized with copolymers of alpha beta-ethylenically unsaturated hydrophobic monomers and ammoniated carboxylic acid comonomers

ABSTRACT

Cellulosic materials such as paper are internally sized by treating fibers of the cellulosic material, e.g., paper pulp, with a copolymer of an Alpha , Beta -ethylenically unsaturated hydrophobic monomer and an ammoniated Alpha , Beta ethylenically unsaturated carboxylic acid and a reaction product of epihalohydrin and ammonia. Internal sizing of the cellulosic material by this method can be carried out under acidic, neutral or basic conditions.

United States Patent Vaughn et al.

[4 1 Aug. 12, 1975 CELLULOSIC MATERIALS INTERNALLY SIZED WITH COPOLYMERSOF ALPHA BETA-ETI-IYLENICALLY UNSATURATED l-IYDROPHOBIC MONOMERS ANDAMMONIATED CARBOXYLIC ACID COMONOMERS Inventors: Walter Lee Vaughn, LakeJackson;

Robert James Beam, Angleton, both of Tex.

The Dow Chemical Company, Midland, Mich.

Filed: Feb. 1, 1974 Appl. No.: 438,913

Assignee:

US. Cl. 162/168; 162/164; 162/169; 162/175; 162/185; 260/17.4 CL;260/17.4 ST; 260/897 A Int. Cl C08g 45/18 Field of Search 260/17.4 CL,17.4 ST; l62/164,168,175,l85,169

References Cited UNITED STATES PATENTS 4/1971 Brown et al. 162/1584/1972 Baggett 162/164 7/1972 Purcell 260/897 OTHER PUBLICATIONS UnionCarbide BrochureF42958; Products for Paper; PC4-300 An AlkaliDispersible Ethylene Copolymer, Printed 10/70; pp. l-2, 11-12 and 14.

Primary ExaminerMorris Liebman Assistant ExaminerEdward WoodberryAttorney, Agent, or Firm-Richard G. Waterman; Michael S. Jenkins 2ABSTRACT 21 Claims, N0 Drawings CELLULOSIC MATERIALS INTERNALLY'SIZEDWITH COPOLYMERS OF ALPHA BETA-ETI-IYLENICALLY UNSATURATED I-IYDROPHOBICMONOMERS AND AMMONIATED CARBOXYLIC ACID COMONOMERS BACKGROUND OF THEINVENTION This invention relates to internal sizing of cellulosicmaterial over the complete range of pH conditions which are normallyencountered in the cellulosic manufacturing arts.

Cellulosic materials such as paper and paperboard, are often sized withvarious materials with the purpose of increasing their resistance towater penetration as well as to penetration by other types of aqueoussolutions. These materials are referred to as sizes or sizing agents andthey may be introduced during the actual manufacture of the cellulosicmaterial, e.g., paper making operation, wherein the process is known asinternal sizing, often called beater sizing, wet end sizing or enginesizing. Surface sizing cellulosic materials by applying sizing agent tofabricated sheet or web is also well known; but is usually considered tobe substantially different from internal sizing.

The basis of present internal sizing methods is the intimate coating ofthe individual fibers of the cellulosic material with a material whichis insoluble in most materials and is repellant to water. For example,in manufacture of paper, the substance originally and still most widelyused for this purpose is rosin or fatty acid. In order to insure themost intimate contact between the rosin and the pulp fiber, the formeris added in either the dissolved state or as a finely dispersedemulsion. It is followed by a precipitating agent, usually aluminumsulfate, known to the paper maker as alum. The alum coagulates therosin, i.e., throws it out of solution or emulsion as a gelatinousprecipitate. Since the rosin or emulsion is first mixed thoroughly withthe pulp in the beater, the precipitate has a maximum chance of adheringto and being subsequently retained by the pulp. When the pulp is madeinto paper, the rosin in contact with the pulp adheres to the pulp assmall particles, e.g., particles having diameters of one micron or less.The paper having the small particles of rosin adhered to the fibersexhibits the desired strength and ink and water resistance.

In addition to rosins, various water-repellant or hydrophobic materialshave been utilized as internal sizing agents. These include fortifiedrosin, mixtures or rosins with waxes, wax emulsions, ketene dimeremulsions, fluorocarbons, fatty acid complexes of chromium or aluminumchlorides, long chain thermoplastic copolymers, as well as thermosettingcondensation-type resins. Although all of these materials are effectiveunder certain conditions, their use is nonetheless subject to one ormore limitations.

For example, in the case of rosin, it is only useful as sizing agent inacidic solutions and therefore cannot be used for the sizing of neutralor alkaline pulps. Rosin is inoperable with the latter since it mustordinarily be used in combination with alum, or an acidic aluminum iondonor which is present for the purpose of precipatating and setting themetal rosinate onto the fibers. The use of alum for this purpose is,however, precluded under neutral or alkaline stock conditions. This is adefinite disadvantage in paper making since paper produced from neutralor alkaline pulp has been found to have higher strength, greaterstability and superior aging characteristics in comparison with paperprepared from acidic pulp. Also, the internal use of alkaline pigmentssuch as calcium carbonate is precluded. This limitation also applies tomost wax emulsions which cannot be used on the alkaline side since theyare usually combined with small quantities of alum for the purpose ofbreaking the emulsions. On the other hand, it may be noted that certainsizing agents will not tolerate acidic conditions. In addition to theabove described pI-I limitations, the water resistance or water holdoutwhich is obtainable with many of the heretofore employed sizing agentsis often inadequate for many applications which require paper orpaperboard displaying an exceptionally high degree of waterresistance.Some sizing agents provide complete water repellancy as opposed to thedesired limited amount of water-resistance. Many sizing agents have beenfound to be incompatible with pigments, fillers or other in gredientswhich are often added to the paper. A further disadvantage of somesizing agents is that a considerable degree of heat curing is requiredin order to develop full effectiveness.

For these and other reasons, it would be highly desirable to provide aninternal sizing agent which can be effectively employed under acidic,neutral or alkaline conditions and which can be cured to a size havingthe desired limited water resistance under normal drying conditions usedin the early stages of manufacturing paper and other cellulosicmaterials.

SUMMARY OF THE INVENTION In the present invention, paper and othercellulosic materials are internally sized under pH conditions rangingfrom moderately acidic through strongly alkaline by an improved internalsizing method. In this improved method for internally sizing thecellulosic material wherein an internal sizing agent is applied to thefibers of the cellulosic material, the improvement comprises the use ofa copolymer of an 01,,B-ethylenically unsaturated hydrophobic monomerand an ammoniated a, B-ethylenically unsaturated carboxylic acid as aninternal sizing agent and as a retention aid, a reaction product ofepihalohydrin and ammonia, or an aliphatic polyamine having at least twoamine hydrogens per molecule or mixture of ammonia and polyamine. Inanother aspect, this invention is an internal sizing composition for acellulosic material comprising a sizing amount of the aforementionedcopolymer and an amount of the aforementioned retentionaid which iseffective to retain the copolymer on the cellulosic material. In afurther aspect, this invention is a cellulosic material internally sizedwith the aforementioned composition. The resultant internally sizedcellulosic material displays a very desirable degree of water-resistancealong with resistance to acidic and alkaline solutions. Of primeimportance is the fact that the successful use of the aforementionedcopolymers as sizing agents in combination with the aforementionedcationic retention aid is not restricted to acidic pH which thus allowsutilization of such sizing agents in the treatment of neutral andalkaline pulp as well as acidic pulp. Furthermore, it is found that onlymild drying and curing conditions are needed to develop the full sizingvalue of such internal sizing agents. I

DETAILED DESCRIPTION OF THE INVENTION For the purposes of thisinvention, the term cellulosic material is meant to include paper, paperboard and other fibrous, sheet-like or molded masses derived from wood,wood pulp, or cotton or other sources of cellulosic fibers. This termalso includes sheet-like or molded masses prepared from combination ofcellulosic materials and non-cellulosic materials such as polyamides,polyesters, polyacrylic acid resin fibers and mineral fibers such asasbestos, glass and the like.

By the term internal-sizing is meant a method of sizing in which thecellulosic material in raw form, e.g., fibrous stock such as paper pulp,is contacted with the sizing agent under conditions effective to sizethe cellulosic material, i.e., deposit the sizing agent on the fibersand cure it to full sizingeffectiveness. Accordingly, it is understoodthat the term internal sizing is generic, and therefore includes suchterms as beater-sizing, engine-sizing, internal wet end sizing and thelike.

The internal sizing agents suitably employed in the practice of thisinvention are copolymers of a,,B-ethylenically unsaturated hydrophobicmonomer and ammoniated :,[3-ethylenically unsaturated carboxylic acid,i.e., a,B-ethylenically unsaturated carboxylic acid in the ammonium saltform. Generally, such copolymers are water-dispersible, semi-solid orsolid materials. Such copolymers have molecular weights which give meltflow viscosities in the range from about 0.2 decigram/minute as measuredby ASTM D-l238- 65T(E) to about 50 decigrams/minute as measured usingthe procedure of ASTM D-l238-65T(B) except that in said procedure theorifice of the extrusion plastometer is 0.020 inch. Preferably, thecopolymer has a number average molecular weight, as determined byebulliometry, in the range from about 1,000 to about 10,000 and a meltflow viscosity in the range from about 0.5 to about 50 decigrams/minuteas determined by ASTM Dl238-65T(B) using the plastomer with a 0.020 inchorifice. Preferred copolymers are also filmforming at temperatures usedin the sizing operation. By water-dispersible is meant a material whichcan exist in the form of a stable aqueous colloidal dispersion in theabsence of a surface active agent. In addition, the copolymers in theform of aqueous dispersions preferably form films under ambientconditions which films dry to form water-insoluble coatings. Bya,B-ethylenically unsaturated hydrophobic monomer is meant anywater-immiscible monomer containing a terminal double bond capable ofpolymerization under normal conditions of addition polymerization toform a waterinsoluble homopolymer having a polyethylenic backbone. Bya,B-ethylenically unsaturated carboxylic acid is meant ana,/3-ethylenically unsaturated carboxylic acid which is capable ofaddition copolymerization through the ethylenically unsaturated groupwith the a,fi-ethylcnically unsaturated hydrophobic monomer. Byammoniated afi-ethylenically unsaturated carboxylic acid is meant thatin the copolymer the carboxylic acid groups are neutralized withammonia.

Preferably, the internal sizing agent is a normally solid, waterandalkali-insoluble thermoplastic addition copolymer in the form of a fluidaqueous colloidal dispersion. The occurrence of ammoniated acid groupsin the polymer should be general throughout the mac romoleeules thereofso that each macromolecule contains a minimum number of active saltgroups sufficient to render the polymer water-dispersible as definedhereinbefore. The maximum number of ammoniated acid groups which may bepresent in the macromolecules is fixed by the requirement that themolecule be substantially water-insoluble. Generally speaking, suchcopolymers contain from about 6 to about 40 weight percent of ammoniatedacid comonomer, with preferred copolymers containing from about 10 toabout 20 weight percent of ammoniated acid comonomer and especiallypreferred copolymers containing from about 15 to about 18 weightpercent.

Exemplary preferred copolymers are the random copolymer products ofcopolymerization of mixtures of one or more polymerizable ethylenicallyunsaturated carboxylic acids having 3 to 8 carbon atoms inclusive ofanhydrides and alkyl half esters of ethylenically unsaturated acids suchas acrylic acid, methacrylic acid, maleic acid and anhydride, itaconicacid, fumaric acid, crotonic acid and citraconic acid and anhydride,methyl hydrogen maleate, ethyl hydrogen maleate, and one or moreafi-ethylenically unsaturated hydrocarbon monomers such as the aliphatica-olefin monomers, e.g, ethylene, propylene, butene-l and isobutene;conjugated dienes, e.g., butadiene and isoprene; and monovinylidenearomatic carbocyclic monomers, e.g., styrene, a-methylstyrene, toluene,and t-butylstyrene. In addition, other ethylenically unsaturatedhydrophobic monomers which are not entirely hydrocarbon arecopolymerized with the aforementioned acid comonomers. Examples of suchsuitable monomers which are not entirely hydrocarbon include esters ofa,B-ethylenically unsaturated carboxylic acids such as ethyl acrylate,methyl methacrylate, ethyl methacrylate, methyl acrylate, isobutylacrylate, and methyl fumarate; unsaturated esters of non-polymerizablecarboxylic acids such as vinyl acetate, vinyl propionate, and vinylbenzoate; vinyl halides such as vinyl and vinylidene chloride; vinylethers; a,B-ethylenically unsaturated amides and nitriles such asacrylamide, acrylonitrile, methacrylonitrile and fumaronitrile. It isunderstood that the aforementioned suitable hydrophobic monomers may becopolymerized with preferred hydrocarbon monomer and the acid comonomerin proportions such that a waterand alkali-insoluble polymer isprovided. Preferred copolymers include copolymers from about to aboutweight percent of ethylene, from about 10 to about 20 weight percent ofone or more ammoniated ethylenically unsaturated acids such as acrylicacid and methacrylic acid and from 0 to about 20 weight percent ofsuitable ethylenically unsaturated hydrophobic monomer as describedhereinbefore such as acrylonitrile, ethyl acrylate and vinyl acetate.

Other copolymers which are suitable are made from preformed, non-acidpolymers by subsequent chemical reactions carried out thereon. Forexample, the carboxylic acid group may be supplied by grafting a monomersuch as acrylic acid or maleic acid onto a polymer substrate such aspolyethylene. Additionally, copolymers containing carboxylic anhydride,ester, amide, acylhalide and nitrile groups can be hydrolyzed tocarboxylic acid groups which can then be neutralized to form theammoniated carboxylic acid.

It is further understood that the a,B-ethylenically unsaturatedcarboxylic acid in ammonium salt form may be copolymerized with thehydrophobic monomer in order to prepare a suitable copolymer.

Specified procedures and means for making the polymers are known to theart as exemplified by US. Pat. No. 3,520,861 to Thomson et al. and US.Pat. No. 3,426,363 to Helin. Preferred low molecular weight copolymersare prepared according to methods disclosed in the foregoing referencesexcept that a telogen such as propylene is employed in the reactionmixture. In instances wherein the acid copolymer is obtained in massform, the copolymer may be converted to aqueous colloidal dispersion inaccordance with the methods of Us. Pat. No. 3,389,109 to Harmon et al.which is subsequently concentrated and ammoniated by the methoddescribed in US. Pat. No. 3,644,258 to Moore et al. Generally methods ofproducing the aqueous colloidal dispersion of a copolymer which requirethe use of little or no emulsifier or other surface active agents arepreferred. Preferably, the aqueous colloidal dispersion of copolymer hasa polymer solids content from about 5 to about 60 weight percent andsuffieient stabilizing ammonia to give the dispersion a pH of at leastabout 7.5. High solids dispersions are suitably prepared from lowersolids dispersions by the method disclosed in the aforementioned patentto Moore et al.

In order to obtain a degree of sizing which is useful in manufacture ofsized paper (including highly sized paper), it is necessary to utilizethe copolymer sizing agent of the present invention in conjunction witha reaction product of epihalohydrin and ammonia, or an aliphaticpolyamine having at least two amine hydrogens per molecule or a mixtureof the polyamine and ammonia, hereinafter collectively referred to asepihalohydrin/amine reaction product. These epihalohydrin/amine reactionproducts are useful as co-additives which enhance the retention of thecopolymer sizing agent and which bring the copolymer sizing agent incloser proximity to the fibers of the cellulosic materials during thesizing operation. Suitable epihalohydrin/amine reaction products arewater dispersible, preferably Water-soluble. Generally such waterdispersible reaction products have molecular weights in the range fromabout 1000 to about 80,000. Preferred reaction products comprise fromabout 0.9 to about 2.]. especially from about 1.5 to about 1.7, mole ofepihalohydrin per mole of amine, i.e., ammonia, polyamine or mixturethereof. Generally, such preferred reaction products have one or moremolecular weight peaks as determined by gel permeation chromatographyand such peaks normally occur in the range from about 2,000 to about70,000. Especially preferred reaction products are those exhibiting atleast one peak in the molecular weight range from about 40,000 to about70.000 Such reaction products, including their method of preparation,are further described in US. 3,655,506 to Baggett which is herebyincorporated by reference in its entirety.

In the internal sizing of paper and other cellulosic materials using theabove-described copolymers as internal sizing agents, a number ofvariations and tech niques may be employed. It is critical however, thatall of the techniques employed achieve uniform dispersal of the sizingagent throughout the cellulosic fiber during internal sizing. Uniformdispersal may be obtained by adding the ammoniated copolymer sizingagent in a fuller dispersed form such as an aqueous colloidaldispersion.

in order to achieve maximum distribution of the copolymer sizing agenton the fiber stock and to avoid tion product to the fiber stock, caremust be taken to avoid contact of the ammoniated copolymer and thereaction product prior to contacting the fiber stock.

The actual addition to the cellulosic material fiber of either thereaction product or the sizing agent may take place at any point in thecellulosic material manufacturing process prior to the ultimateconversion of wetfibrous material into web, sheet or molded article.Thus, for example, in paper manufacture, the sizing agent may be addedto the pulp while the latter is in the head box, beater, hydropulper orstock chest.

In order to obtain good internal sizing, it is desirable that theammoniated copolymer sizing agents be uniformly dispersed throughout thefiber in as small a particle size as is possible to obtain. One methodfor providing such uniform dispersions is to disperse the sizing agentin aqueous media prior to its addition to stock using, for example, amethod as described hereinbefore. While it is generally desirable to usethe ammoniated copolymer sizing agent in aqueous colloidal dispersionwhich is free of emulsifiers and surface active agents, such agents canbe suitably employed in the practice of the invention provided that suchagents are fugitive during sizing or otherwise do not impair theeffectiveness of the copolymer sizing agent.

The sizing agents of this invention are most successfully utilized forthe sizing of paper prepared from all types of both cellulosic andcombination of cellulosic with non-cellulosic fibers. The cellulosicfibers which may most advantageously be used include the bleached andunbleached sulfate (kraft), bleached and unbleached sulfite, bleachedand unbleached soda, neutral sulfite, semi-chemical, chemi-ground wood,ground wood and any combination of these fibers. These designationsrefer to wood pulp fibers which have been prepared by means of a varietyof processes which are known in the pulp and paper industries.

It is understood that all types of additives such as pigments, fillers,stabilizers, retention aids, wet strength additives and dry strengthadditives, additional sizing agents, and the like may be employed incombination with the copolymer sizing agents of the present invention.Such additaments include kaolin clay, talc, titanium dioxide, calciumcarbonate, diatomaceous earth, plastic pigments, aluminum trihydrate,and precipitated silica.

The ammoniated copolymer sizing agents are suitably employed in amountseffective to achieve the purposes of the sizing such aswater-resistance, i.e., an amount effective to size the cellulosicmaterial. Generally, amounts ranging from about 0.03 to about 20 weightpercent based on dry weight of the cellulosic material in the finishedsheet or article are suitable, with preferred amounts being in the rangefrom about 0.05 to about 2 weight percent and especially preferredamounts being in the range from about 0.2 to about I weight percent. Itis understood that within this numerical range, the precise amount whichis used will depend for the most part on the type of cellulosic materialwhich is being employed, the specific operating conditions, as well asthe particular end use for which the cellulosic material is destined.For example, paper which will require good water-resistance or inkholdout will necessitate the use of a higher concentration or sizingagent than a paper having characteristics which necessitate the use ofonly small amounts of sizing. Accordingly, any amount which is suitableto effect the desired end result of the sizing is suitable for thepurpose of this invention.

These same factors also apply in relation to the amount ofepihalohydrin/amine reaction product which is used as a retention aid inconjunction with ammoniated copolymer sizing agent. Thus, the skilledartisan will be able to use the reaction product and the sizing agent inany concentrations which is found to be applicable to the specificoperating conditions of internally sizing cellulosic material as definedhereinbefore. However, as a general rule, the epihalohydrin/aminereaction product is usually employed in amount in the range from about0.5 to about weight parts per 1 weight part of copolymer sizing agent,preferably from about 1.5 to about 3 weight parts of the reactionproduct per 1 weight part of copolymer sizing agent.

tained at 16-20C.. 925 g. 10 g. moles) of epichlorohydrin is added overa period of 4 hours. At the end of the addition, the reaction mixture isstirred for another 16 hours at the same temperature, then 330 g. ofwater is added and the mixture is heated to 100C. and cooled to roomtemperature over a 2-hour period. A mixture of 200 parts by weight ofthis prepolymer resin with 100 parts of epichlorohydrin and 200 parts ofwater is stirred at 9598C. for 2 hours and cooled to room temperature.The aqueous dispersion of copolymer and reaction product solution areadded separately to 236 parts of a 0.33 percent solids aqueous slurry ofbleached kraft pulp slurry having a pH of 7.8 which is adjusted to pH4.5 by adding H Handsheets are formed and dried in accordance with TAPPIT-205m- 53. Surface wettability by water (angle of contact) and inkpenetration of the handsheets is determined and recorded in Table 1.

As an additional illustration of this embodiment, a sizing compositioncontaining different amounts of the aqueous dispersion of the copolymerand the reaction product is used for internal sizing of theaforementioned pulp. In the foregoing manner, the treated pulp isconverted to handsheets and tested for surface wettability and inkpenetration. The results are also recorded in Table 1.

TABLE 1 ('opolymer Reaction Product lnk Penetration. SampleConcentration Concentration Reflectance at No. Ih/ton l Type lb/ton l120 sec. (2) Contact Angle (3). precured 1 o NH,,/EP(H* 15 93 103 2 4 NH/EPCH" 15 70 105 Reaction product ofepichloroh drin/ammonia in the moleratio of 1.7:1. said reaction product having molecular weight peaks at5000 and 50.000 as measured by gel permeation chromatography l Measuredin dr weight as pounds of specified additive per (2) A photometricdetermination of black ink penetration lhrough ol'thc paper opposite towhich a pool ofthe hlack ink is applied. The

has a 100'; reflectance.

(3) Surface wettability l\ \\'atcr ((ontaci Angle) he be construed aslimiting its scope. In these examples, all 4 parts and percentages areby weight unless otherwise noted.

EXAMPLE 1 A 500-g portion of ethylene/acrylic acid (87.3/12.7) copolymerhaving a molecular weight peak of 6950 as determined by gel permeationchromatography and a melt flow viscosity [ASTM Dl238-65T(B) using aplastometer having a 0.020 inch orifice] of 2 decigrams/minute is addedto 240 ml of aqueous ammonia (28 percent NH in a 4 liter kettlecontaining 2.94 liters of water. The foregoing ingredients are stirredfor 8 hours at 100C, and the resulting dispersion is allowed to cool toroom temperature. The dispersion is passed through gauze to removeflocculated material. The resulting filtrate is an aqueous dispersioncontaining 13.6 percent ethylene/ammonium acrylate copolymer solids andhaving pH of about 8.

A 5-1iter reaction flask equipped with reflux condenser. stirrer,thermometer. and feeding funnel is charged with 431 g. (7 g. moles) of28-30 percent aqueous ammonia and partially immersed in a cooling bath.With the reaction mixture temperature mainton of pulp.

white or light-colored paper h measuring light reflectance on the sidepaper tested prior to inking. using a black background of0/ reflectancel'orc curing as determined by TAPPl-458m-4N.

EXAMPLE 2 A 7.3-lb. portion of ethylene/acrylic acid (86/14) copolymerhaving a melt flow viscosity (ASTM D1238- T(B) with a 0.020 inchorifice) of 2 decig/min. (number average molecular weight of 4,450) isadded to 7.5 gallons of water and 0.617 gallons of aqueous ammonia (28percent NH in a 10 gallon stirred kettle. The kettle is heated andstirred for 3 hours at C and 45 psi. The product is drained and filteredthrough a 100 mesh stainless steel screen. A good amber coloreddispersion having 10 percent copolymer solids is obtained.

A 4-part portion of the epichlorohydrin/ammonia reaction product as usedin Example 1 is diluted with 27 parts of water. A 2.9-part portion ofthe foregoing copolymer dispersion is diluted with 4.8 parts of water.The two dilutions are added separately to a bleached kraft pulp slurry.The mixture is adjusted to a pH of 3.5 with sulfuric acid. The pulpslurry is formed into a handsheet and tested for ink penetration andwater contact angle. The foregoing procedure is repeated using pulpslurries adjusted to pH values of 4.8, 6.1, 7.1, 7.9, 9.1, and 10.2. Theresults of the foregoing tests which are recorded in Table 11 show thecopolymer sizing agent to be effective over a wide range of pH.

TABLE ll Additive Concentration l 1 lbs/ton Ethylene/Ammoniatcd I lnkPenetration. Sample Acrylic Acid Ammonia/Epichlorohydrin /r Reflectanceat Contact Angle.

No. Copolymer Reaction Product 120 sec. (2) precured (3) pH (4) 1 ll) 159X 1 15 3.5 2 1U 15 9X 120 4.8 3 ll) 15 99 117 6.] 4 1t) 15 99 1 18 7.15 ll) 1()() 122 7.9 6 ll) 15 95 120 9.1 7 ll) 15 )8 118 10.2

(I Same as in Table I.

(2) Same as in Table l.

(3) Same as in Table l. (4) pH of pulp slurry before processing intohandsheets.

EXAMPLE 3 EXAMPLE 4 A -g. portion of ethylene/acrylic acid (89/11)copolymer having a melt flow viscosity [ASTM D-l 238- T(B) with a 0.20inch orifice] of 43 decig./min. (number average molecular weight of4,075) is added to 27 g. of aqueous ammonia (28 percent of NH;;) and 200g. of water in a 0.5 liter stainless steel bomb reactor. The bomb issealed and the reaction mixture is shaken for 3 hours at C. Theresulting dispersion contains 15 percent copolymer solids A 0.18-partportion of epichlorohydrin/ammonia reaction product as used in Example 1is diluted with 6 parts of water. The resulting solution is added to ableached kraft pulp slurry in the proportion set forth in Table 111 andis stirred for one minute. A 0.19-part portion of the foregoing ethylenecopolymer dispersion is diluted with 7.7 parts of water and is thenadded to the pulp slurry as an internal size in the proportion specifiedin Table 111. The pH of the resulting pulp slurry is adjusted to 4.5with sulfuric acid. The pulp is formed into a handsheet and is testedfor ink penetration and water contact angle. The results are listed inTable lll.

TABLE Ill Following the procedure of Example 1, an aqueous dispersion(11 percent copolymer solids) of ammoniated ethylene/acrylic acid(86/14) copolymer having a number average molecular weight of 4,500 isprepared.

An aqueous solution of a retention aid as specified in Table IV is addedin proportions specified in Table IV to a bleached kraft pulp slurry(0.3 percent solids in water) while stirring. The ammoniated copolymerdispersion is then added to the stirred pulp slurry in the amountindicated in Table IV. The pulp slurry is converted to handsheets anddried in accordance with TAPPl T-205m-53. Surface wettability by water(angle of contact) and ink penetration of the dried handsheets are thendetermined. The results are recorded in Table For the purpose ofcomparison, the foregoing procedure is followed except that a cationicstarch is employed as a retention aid. The resultant handsheets arelikewise tested for surface wettability and ink penetration. Theseresults are also recorded in Table IV.

Additive Concentration 1 lhs/ton Ammimia/Epichlorohydrin lnkPenetration. "/1 Reflectance at Contact Angle.

Sample Ethylene Copolymer Reaction Product 121) sec. (2) precured (3) (1P13) Same as in Table 1.

TABLE IV Size Retention Aid lnk Sample Concentration ConcentrationBeater Contact Penetration. No. Type lb/ton 1 Type lb/ton 1 pH Angle(3)(2). sec.

*Not an example of the invention. (a)

of BUJIUU.

Ammoniated ethylene/acrylic acid (so/l4) copolymer having a numberaverage molecular weight of Ammoniated ethylene/acrylic acid (NUS/19.51copolymer having a number average molecular weight Ammoniatedethylene/acrylic acid (NU/2U) copolymer having a melt flow viscosity{ASTM DJZ3s-(5 Tl 1'5 1] of 251) dccig/min which approximatelycorresponds to a number average molecular weight of Reaction product ofepichlonihydrin/ammonia in the mole ratio of 1.61:1. said reactionproduct having molecular weight peaks at 2500 and 65.000 as measured bygel permeation chromatography.

Potato starch hearing quaternary amine groups as follows:

('H. .C-CH l\"((HM. and manufactured by A. l-l. Stalcy Manufacturing.

H l l Same as in Table l. (2)

(3) Same as in Table 1.

Time in seconds taken for paper to have an 811% reflectance using testmethod (2) in Table l.

EXAMPLE 5 9. The improvement according to claim 7 wherein the carboxylicacid is methacrylic acid. A SO-pound portion of ethylene/acrylic acid(85/15) 10. The improvement according to claim 7 wherein copolymerhaving a melt flow viscosity of Sdeci g/min, the copolymer isfilm-forming under the conditions of (ASTM D-l 238-65T(E) is added to 75pounds of 5 internal i aqueous ammonia (28 percent NH3) and 75 pounds of11. The improvement of claim 10 wherein the cowater in a 25-gallonstirred kettle. The kettle is heated Polymer has a number averagemolecular We'ght peak at 140C for five hours. The excess ammonia isstripped m the range from about 1,000 to about IOOOO and at 85C and thenthe product is drained from the kettle. tains from .about 10 to aboutweight Percent of afi-ethylemcally unsaturated carboxylic acid.

l The resulting dispersion contains 24 percent copo y l0 12 TheImprovement accordmg to Glam 1 whcrem mer sohds' the cellulosic materialis internally sized under condi- A fLO-part portion of anepichlorohydrin/ammonia tions of pH of at least a prPduct used m ExampleI (25 percent 13. An internal sizing composition for a cellulosicsolids) is diluted with 27 parts of water. A O.l2-part materialComprising a Sizing amount of a watch POrtion of the foregoing ethylenecopolymer dispersion dispersible, waterand alkali-insoluble copolymer ofan is parts Of water. The tWO dilutions are a fl-ethylenicallyunsaturated hydrophobic monomer added to a bleached kraft pulp slurry inthe proportions d an ammoniated g h l i ll unsaturated set forth inTable V. The resulting slurry is adjusted to boxylic acid, saidcopolymer containing from about 6 a pH of 4.5 with sulfuric acid andformed into a handto about 40 weight percent of the ammoniatedcarboxsheet. The handsheet is tested for ink penetration and 20 ylicacid and a water dispersible reaction product of water contact angle andthe results are recorded in epihalohydrin and ammonia, or aliphaticpolyamine Table V. having at least two amine hydrogens per molecule orTABLE V Additive Concentration l lbs/ton lnk Penetration-Ammonia/Epichlorohydrin "/1 Reflectance at Contact An le.

Sample Ethylene Copolymer Reaction Product 120 sec. (2) precured l in l589 92 (l)( 3) Same as in Table 1.

mixture of ammonia and the polyamine in an amount effective to retainthe copolymer on the cellulosic material.

14. The composition according to claim 13 wherein the reaction producthas at least one molecular weight peak as determined by gel permeationchromatography What is claimed is:

1. In a method for internal sizing ofa cellulosic material wherein aninternal sizing agent and a retention aid are applied to the fibers ofthe cellulosic material, the improvement wherein the internal sizingagent is a water-dispersible, waterand alkali-insoluble copolymer of anafi-ethylenically unsaturated hydrophobic m the range from #2 9 to about3 monomer and an ammoniated a,B-ethylenically unsat- The of claim wheremi rem;-

40 tion product is water soluble and the mole ratio of epiuiatedarboxyliir acid and the retimtion is a i halohydrin to amine is fromabout 0.9 to about 2.1 dispersible reaction product of epihalohydrin andam mole of epihalohydrin to 1 mole of amine.

f or an ahphanc polyamme hav mg at least two 16. The compositionaccording to claim 13 wherein ainme hydfogePs per moiecule or a mlxtureof ammothe hydrophobic monomer is ethylene and the carboxnia andaliphatic polyamine. ylic acid is acrylic acid.

2. The improvement of claim 1 wherein the reaction The Composition ofclaim 13 wherein the hydro product has at least one molecular weightpeak as dephobic monomer f the copolymer is ethy]ene termined y gelPermeation Chromatography in the 18. A cellulosic material internallysized with waterrange from about 2,000 to about 70,000. dispersible,waterand alkali-insoluble copolymer of an 3. The improvement accordingto claim 1 wherein 5O a,,8-ethylenically unsaturated hydrophobic monomerthe reaction product is water soluble and the mole ratio and anammoniated a,,8 ethylenically unsaturated carof epihalohydrin to amine ifrom ab t 9 to about boxylic acid, and a water-dispersible reactionproduct 2.1 mole of e ihalohydrin t 1 l f i of epihalohydrin andammonia, aliphatic polyamine 4. The improvement according to claim 1wherein having at least two amine hydrogens per molecule or thecellulosic material is pulp. mixture thereof.

5. The improvement according to laim 1 wherei 19. The cellulosicmaterial of claim 18 wherein the the hydrophobic monomer is ana,B-ethylenically uncopolymer contains from about l0 to about 20 weightsaturated hydrocarbon. percent of the carboxylic acid.

6. The improvement according to claim 5 wherein 20. The cellulosicmaterial of claim 18 wherein the the hydrocarbon is an aliphatica-monoolefin having 2 cellulosic material is paper. to l4 carbon atoms.21. The cellulosic material of claim 18 wherein the 7. The improvementaccording to claim 6 wherein reaction product is water-soluble and themole ratio of the aliphatic a-monoolefin is ethylene. epihalohydrin toamine is from about 0.9 to about 2.1

8. The improvement according to claim 7 wherein mole of epihalohydrin toone mole of amine.

the carboxylic acid is acrylic acid.

1. IN A METHOD FOR INTERNAL SIZING OF A CELLULOSIC MATERIAL WHEREIN ANINTERNAL SIZING AGENT AND A RETENTION AID ARE APPLIED TO THE FIBERS OFTHE CELLULOSIC MATERIAL, THE IMPROVEMENT WHEREIN THE INTERNAL SIZINGAGENT IS A WATER-DISPERSIBLE, WATERAND ALKALI-INSOLUBLE COPLYMER OF ANA,B-ETHLENICALLY UNSATURATED HYDROPHOBIC MONOMER AND AN AMMONIATEDA,BETHYLENICALLY UNSATURED CARBOXYLIC ACID AND THE RETENSION AID IS AWATER DISPERSIBLE REACTION PRODUCT OF EPHALOHYDRIN AND AMMONIA, OR ANALIPHATIC POLYMINE HAVING AT LEAST TWO AMINE HYDROGENS PER MOLECULE OR AMIXTURE OF AMMONIA AND ALIPHATIC POLYAMINE.
 2. The improvement of claim1 wherein the reaction product has at least one molecular weight peak asdetermined by gel permeation chromatography in the range from about2,000 to about 70,000.
 3. The improvement according to claim 1 whereinthe reaction product is water soluble and the mole ratio ofepihalohydrin to amine is from about 0.9 to about 2.1 mole ofepihalohydrin to 1 mole of amine.
 4. The improvement according to claim1 wherein the cellulosic material is pulp.
 5. The improvement accordingto claim 1 wherein the hydrophobic monomer is an Alpha , Beta-ethylenically unsaturated hydrocarbon.
 6. The improvement according toclaim 5 wherein the hydrocarbon is an aliphatic Alpha -monoolefin having2 to 14 carbon atoms.
 7. The improvement according to claim 6 whereinthe aliphatic Alpha -monoolefin is ethylene.
 8. The improvementaccording to claim 7 wherein the carboxylic acid is acrylic acid.
 9. Theimprovement according to claim 7 wherein the carboxylic acid ismethacrylic acid.
 10. The improvement according to claim 7 wherein thecopolymer is film-forming under the conditions of internal sizing. 11.The improvement of claim 10 wherein the copolymer has a number averagemolecular weight peak in the range from about 1, 000 to about 10,000 andcontains from about 10 to about 20 weight percent of Alpha , Beta-ethylenically unsaturated carboxylic acid.
 12. The improvementaccording to claim 1 wherein the cellulosic material is internally sizedunder conditions of pH of at least
 7. 13. An internal sizing compositionfor a cellulosic material comprising a sizing amount of awater-dispersible, water- and alkali-insoluble copolymer of an Alpha ,Beta -ethylenically unsaturated hydrophobic monomer and an ammoniatedAlpha , Beta -ethylenically unsaturated carboxylic acid, said copolymercontaining from about 6 to about 40 weight percent of the ammoniatedcarboxylic acid and a water dispersible reaction product ofepihalohydrin and ammonia, or aliphatic polyamine having at least twoamine hydrogens per molecule or mixture of ammonia and the polyamine inan amount effective to retain the copolymer on the cellulosic material.14. The composition according to claim 13 wherein the reaction producthas at least one molecular weight peak as determined by gel permeationchromatography in the range from about 2,000 to about 70,000.
 15. Thecomposition of claim 14 wherein the reaction product is water solubleand the mole ratio of epihalohydrin to amine is from about 0.9 to about2.1 mole of epihalohydrin to 1 mole of amine.
 16. The compositionaccording to claim 13 wherein the hydrophobic monomer is ethylene andthe carboxylic acid is acrylic acid.
 17. The composition of claim 13wherein the hydrophobic monomer of the copolymer is ethylene.
 18. Acellulosic material internally sized with water-dispersible, water- andalkali-insoluble copolymer of an Alpha , Beta -ethylenically unsaturatedhydrophobic monomer and an ammoniated Alpha , Beta -ethylenicallyunsaturated carboxylic acid, and a water-dispersible reaction product ofepihalohydrin and ammonia, aliphatic polyamine having at least two aminehydrogens per molecule or mixture thereof.
 19. The cellulosic materialof claim 18 wherein the copolymer contains from about 10 to about 20weight percent of the carboxylic acid.
 20. The cellulosic material ofclaim 18 wherein the cellulosic material is paper.
 21. The cellulosicmaterial of claim 18 wherein the reaction product is water-soluble andthe mole ratio of epihalohydrin to amine is from about 0.9 to about 2.1mole of epihalohydrin to one mole of amine.